An evaporation process refers to a process of placing a material for film-forming in a vacuum and evaporating or sublimating to coat it on a substrate in a vacuum environment, which is also called a vacuum evaporation or a vacuum coating.
Generally, when evaporating an organic material, it is necessary to use a high-accuracy metal mask for blocking between the organic material and the substrate, so as to form a patterned film layer by evaporation. Taking an evaporation film layer in a display technical field for example, the high-accuracy metal mask is mainly used for ensuring an accuracy of an evaporation position, determining a fine degree of a pattern formed by evaporation, and determining a number of pixels formed by evaporation. It can be seen that, specific parameters of the high-accuracy metal mask used in the process of evaporation to some extend determines a yield of product.